core.sync.mutex

The mutex module provides a primitive for maintaining mutually exclusive access.

License:

Boost License 1.0

Authors:

Sean Kelly

Source

core/sync/mutex.d

class Mutex: object.Object.Monitor

This class represents a general purpose, recursive mutex.

Implemented using pthread_mutex on Posix and CRITICAL_SECTION on Windows.

Examples:

import core.thread : Thread;

class Resource
{
    Mutex mtx;
    int cargo;

    this() shared @safe nothrow
    {
        mtx = new shared Mutex();
        cargo = 42;
    }

    void useResource() shared @safe nothrow @nogc
    {
        mtx.lock_nothrow();
        cargo++;
        mtx.unlock_nothrow();
    }
}

shared Resource res = new shared Resource();

auto otherThread = new Thread(
{
    foreach (i; 0 .. 10000)
        res.useResource();
}).start();

foreach (i; 0 .. 10000)
    res.useResource();

otherThread.join();

assert (res.cargo == 20042);

nothrow @nogc @trusted this()
shared nothrow @nogc @trusted this()

Initializes a mutex object.

nothrow @nogc @trusted this(Object obj)
shared nothrow @nogc @trusted this(Object obj)

Initializes a mutex object and sets it as the monitor for obj.

In

obj must not already have a monitor.

@trusted void lock()
shared @trusted void lock()
final nothrow @nogc @trusted void lock_nothrow(this Q)()

Constraints:
if (is(Q == Mutex) || is(Q == shared(Mutex)))

If this lock is not already held by the caller, the lock is acquired, then the internal counter is incremented by one.

Note

Mutex.lock does not throw, but a class derived from Mutex can throw. Use lock_nothrow in nothrow @nogc code.

@trusted void unlock()
shared @trusted void unlock()
final nothrow @nogc @trusted void unlock_nothrow(this Q)()

Constraints:
if (is(Q == Mutex) || is(Q == shared(Mutex)))

Decrements the internal lock count by one. If this brings the count to zero, the lock is released.

Note

Mutex.unlock does not throw, but a class derived from Mutex can throw. Use unlock_nothrow in nothrow @nogc code.

@trusted bool tryLock()
shared @trusted bool tryLock()
final nothrow @nogc @trusted bool tryLock_nothrow(this Q)()

Constraints:
if (is(Q == Mutex) || is(Q == shared(Mutex)))

If the lock is held by another caller, the method returns. Otherwise, the lock is acquired if it is not already held, and then the internal counter is incremented by one.

Returns:

true if the lock was acquired and false if not.

Note

Mutex.tryLock does not throw, but a class derived from Mutex can throw. Use tryLock_nothrow in nothrow @nogc code.